Nov 24, 2009

Suggested Thresholds for Essential Counters

This is excerpted from an MS article for w2k resource kit. Most of the numbers should still be applicable to newer version of OSes.

Resource
Object/Counter
Threshold
Comments

Disk
PhysicalDisk\% Disk Time
90%

Disk
PhysicalDisk\ Disk Reads/sec, PhysicalDisk\Disk
Depends on manufacturer's specifications
Check the disk's specified transfer rate to verify that the logged rate doesn't exceed specifications.(1)



Disk
PhysicalDisk\ Current Disk Queue Length
Number of spindles plus 2
This is an instantaneous counter; observe its value over several intervals. For an average over time, use PhysicalDisk\ Avg. Disk Queue Length

Memory
Memory\Available Bytes
Less than 4 MB
Research memory usage, and then add memory, if needed.

Memory
Memory\Pages/sec
20
Research paging activity, the activity that occurs when data is swapped out of memory and stored on disk when memory is low.

Network
Network Segment\% Net utilization
Depends on network type
For Ethernet networks, the recommended threshold is 30 percent.

Paging File
Paging File\% Usage
99%
Review this value in conjunction with Available Bytes and Pages/sec to understand paging activity on your system.

Processor
Processor\% Processor Time
85%
Isolate the process that is using a high percentage of processor time. Upgrade to a faster processor, or install an additional processor.

Processor
Processor\ Interrupts/sec
Depends on the processor
A dramatic increase in this counter with a corresponding increase in system activity indicates a hardware problem. Identify the network adapter that is causing the interrupts.

Server
Server\Bytes Total/sec
If the sum Bytes for all servers is roughly equal to the maximum transfer rates for your network, you might need to segment the network.

Server
Server\Work Item Shortages
3
If this value reaches the threshold, consider tuning InitWorkItems or MaxWorkItems in the registry.

Server
Server\Pool Paged Peak
Amount of physical RAM
This value indicates the maximum paging file size and the amount of physical memory.

Server
Server Work Queues\Queue Length
4
If this value reaches the threshold, there may be a processor bottleneck. This is an instantaneous counter; observe it over several intervals.

Multiple Processors
System\Processor Queue Length
2
This is an instantaneous counter; observe it over several intervals.